The flat foot is a frequent deformity in children and results in various levels of functional alterations. A diagnosis based on foot morphology is not sufficient to define the therapeutic approach. In fact, the degree of severity of the deformity and the effects of treatments require careful functional assessment. In case of functional flatfoot, subtalar arthroereisis is the surgical treatment of choice. The aim of this study is to evaluate and compare the functional outcomes of two different bioabsorbable implants designed for subtalar arthroereisis in childhood severe flat foot by means of thorough gait analysis. Ten children (11.3 ± 1.6 yrs, 19.7 ± 2.8 BMI) were operated for flat foot correction [1,2] in both feet, one with the calcaneo-stop method, i.e. a screw implanted into the calcaneus, the other with an endoprosthesis implanted into the sinus-tarsi. Gait analysis was performed pre- and 24 month post-operatively using a 8-camera motion system (Vicon, UK) and a surface EMG system (Cometa, Italy) to detect muscular activation of the main lower limb muscles. A combination of established protocols, for lower limb [3] and multi-segment foot [4] kinematic analysis, was used to calculate joint rotations and moments during three level walking trials for each patient. At the foot, the tibio-talar, Chopart, Lisfranc, 1st metatarso-phalangeal joints were tracked in three-dimensions, together with the medial longitudinal arch. Significant differences in standard X-ray measurements were observed between pre- and post-op, but not between the two treatment groups. Analysis of the kinematic variables revealed functional improvements after surgery. In particular, a reduction of eversion between the shank and calcaneus (about 15° on average) and a reduction of inversion between metatarsus and calcaneus (about 18° on average) were detected between pre- and post-operatively after both treatments. Activation of the main plantar/dorsiflexor muscles was similar at both pre- and post-op assessments with both implants. The combined lower limb and multi-segment foot kinematic analyses were found adequate to provide accurate functional assessment of the feet and of the lower limbs. Both surgical treatments restored nearly normal kinematics of the foot and of the lower limb joints, associated also to a physiologic muscular activation.
In total knee arthroplasty (TKA), the effectiveness of the mechanical alignment (MA) within 0°±3° has been recently questioned. A novel implantation approach, i.e. the kinematic alignment (KA), emerged recently, this being based on the pre-arthritic lower-limb alignment. In KA, the trans-cylindrical axis is used as the reference, instead of the trans-epicondylar one, for femoral component alignment. This axis is defined as the line passing through the centres of the posterior femoral condyles modeled as cylinders. Recently, patient specific instrumentation (PSI) has been introduced in TKA as an alternative to conventional instrumentation. This provides a tool for preoperative implant planning also via KA. Particularly, KA using PSI seems to be more effective in restoring normal joint kinematics and muscle activity. The purpose of this study was to report preliminarily joint kinematic and electromyography results of two patient groups operated via conventional MA or KA, the latter using PSI. Twenty patients recruited for TKA were implanted with Triathlon® prosthesis (Stryker®-Orthopaedics, Mahwah, NJ-USA). Seventeen patients, eleven operated targeting MA using the convention instrumentation (group A) and six targeting KA (group B) using PSI (Stryker®-Orthopaedics), were assessed at 6 month follow-up clinically via IKSS and biomechanically. Knee kinematics during stair-climbing, chair-rising, and extension-against-gravity were evaluated using three-dimensional mono-planar video-fluoroscopy (CAT® Medical-System, Monterotondo, Italy) synchronised with electromyography (Wave-Wireless, Cometa®, Milan, Italy). Component pose was reconstructed to calculate knee flexion/extension (FE), ad/abduction (AA), internal/external-rotation (IE), together with the rotation of the contact-line (CLR), i.e. line connecting the medial (MCP) and lateral (LCP) tibio-femoral contact points. MCP and LCP antero-posterior translations were calculated and reported in percentage (%) of the tibial base-plate length.INTRODUCTION
PATIENT AND METHODS
The period of post-operative treatment before surgical wounds
are completely closed remains a key window, during which one can
apply new technologies that can minimise complications. One such
technology is the use of negative pressure wound therapy to manage
and accelerate healing of the closed incisional wound (incisional
NPWT). We undertook a literature review of this emerging indication
to identify evidence within orthopaedic surgery and other surgical
disciplines. Literature that supports our current understanding
of the mechanisms of action was also reviewed in detail. Objectives
Methods
In computer-aided total knee arthroplasty (TKA), surgical navigation systems (SNS) allow accurate tibio-femoral joint (TFJ) prosthesis implantation only. Unfortunately, TKA alters also normal patello-femoral joint (PFJ) functioning. Particularly, without patellar resurfacing, PFJ kinematics is influenced by TFJ implantation; with resurfacing, this is further affected by patellar implantation. Patellar resurfacing is performed only by visual inspections and a simple calliper, i.e. without computer assistance. Patellar resurfacing and motion via patient-specific bone morphology had been assessed successfully The aim of this study was to report the current experiences Twenty patients with knee gonarthrosis were divided in two cohorts of ten subjects each and implanted with as many fixed-bearing posterior-stabilised prostheses (NRG® and Triathlon®, Stryker®-Orthopaedics, Mahwah, NJ-USA) with patellar resurfacing. Fifteen patients were implanted; five patients of the Triathlon cohort are awaiting hospital admission. TKAs were performed using two SNS (Stryker®-Leibinger, Freiburg-Germany). In addition to the traditional knee SNS (KSNS), the novel procedure implies the use of the patellar SNS (PSNS) equipped with a specially-designed patellar tracker. Standard navigated procedures for intact TFJ survey were performed using KSNS. These were performed also with PSNS together intact PFJ survey. Standard navigated procedures for TFJ implantation were performed using KSNS. During patellar resurfacing, the patellar cutting jig was fixed at the desired position with a plane probe into the saw-blade slot; PSNS captured tracker data to calculate bone cut level/orientation. After sawing, resection accuracy was assessed using a plane probe. TFJ/PFJ kinematics were captured with all three trial components in place for possible adjustments, and after final component cementing. A calliper and pre/post-TKA X-rays were used to check for patellar thickness/alignment.INTRODUCTION
MATERIALS AND METHODS
In Total Knee Arthroplasty (TKA), the neutral overall limb alignment (NOLA), i.e. the mechanical alignment of the lower limb within 0°±3°, is targeted for achieving good clinical/functional results. The kinematic overall limb alignment (KOLA), which uses the axis through the centres of the femur posterior condyles modelled as cylinders, represents a novel approach for achieving better soft tissue balance. Patient-specific instrumentation (PSI) is nowadays offered as an effective technology in TKA to obtain better lower limb alignments than those via conventional guides (CON). Although relevant results are still inconsistent, the benefits claimed include shorter operative time, reduced surgical instrumentation, and accurate preoperative planning. The aim of this study was to report the preliminary clinical and radiological results of TKA patients operated via NOLA-PSI and KOLA-PSI. Comparisons between them and with the results obtained via NOLA-CON were performed. A four-centre randomised study on 144 patients has been designed to assess these three techniques. In each centre, 36 patients are planned to be operated, 12 per technique. Currently, in our centre 18 patients have been operated so far: 6 via NOLA-CON (Group A), 3 via NOLA-PSI (Group B), and 9 via KOLA-PSI (Group C). All patients were implanted with a cruciate-retaining TKA (Triathlon®, Stryker®-Orthopaedics, Mahwah, NJ-USA) with patella resurfacing, those in PSI groups according to Otismed® imaging protocol. This includes pre-operative MRI scans at the hip, knee and ankle joints. Clinical evaluations were performed pre-operatively, at 45 days, and 3, 6 and 12 months post-operatively using the knee and functional IKSS (International Knee Society Score). At 45 days post-operatively a weight-bearing long leg radiograph was performed to measure possible differences between planned and implanted component alignment in patients operated via NOLA groups (A and B) and via KOLA group (C).INTRODUCTION
PATIENTS AND METHODS
We undertook a randomised controlled trial to
compare bipolar hemiarthroplasty (HA) with a novel total hip replacement
(THR) comprising a polycarbonate–urethane (PCU) acetabular component
coupled with a large-diameter metal femoral head for the treatment
of displaced fractures of the femoral neck in elderly patients. Functional
outcome, assessed with the Harris hip score (HHS) at three months
and then annually after surgery, was the primary endpoint. Rates
of revision and complication were secondary endpoints. Based on a power analysis, 96 consecutive patients aged >
70
years were randomised to receive either HA (49) or a PCU-THR (47).
The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22
to 52) for the HA and the PCU group, respectively. The HHS showed no statistically significant difference between
the groups at every follow-up. Higher pain was recorded in the PCU
group at one and two years’ follow-up
(p = 0.006 and p = 0.019, respectively). In the HA group no revision
was performed. In the PCU-THR group six patients underwent revision
and one patient is currently awaiting
re-operation. The three-year survival rate of the PCU-THR group
was 0.841 (95% confidence interval 0.680 to 0.926). Based on our findings we do not recommend the use of the PCU
acetabular component as part of the treatment of patients with fractures
of the femoral neck. Cite this article:
In elderly patients, the incidence of a second fracture in the contralateral hip within 2 years of a femoral neck fracture (FNF), ranges from 7 to 12%. We want to evaluate the safety and efficacy of the Prevention Nail System (PNS), a titanium screw with a hydroxyapatite-coated thread, developed to prevent contralateral FNFs in severe osteoporotic patients.Introduction
Hypothesis
The delay looks radiographically as a fracture callus not very evident or absent 6 months after osteosynthesis. Patients undergo a long period of immobilization and this fact causes the increase the social cost of the disease. The technique we suggest aims to the reduce the period of immobilization and as a consequence the management costs of the disease. Our technique includes the infiltration of the delay focus with platelet rich fibrin, bone marrow concentrated and demineralized bone matrix. Outpatients and radiographic checks were carried out 3, 6 and 12 months after surgery. The treatment was considered fail in case of absence of bone callus at 3 out of 4 corticals at the rx after 6 months from surgery.Introduction
Materials and methods
Despite a large percentage of total knee arthroplasty failures occurs for disorders at the patello-femoral joint (PFJ), current navigation systems report tibio-femoral (TFJ) kinematics only, and do not track the patella. Despite this tracking is made difficult by the small bone and by its full eversion during surgery, a new such technique has been developed, which includes a new tracker, new corresponding surgical instrumentation also for patellar resurfacing, and all relevant software. The aim of this study is to report an early experience in patients of these measurements, i.e. TFJ and PFJ kinematics. These measurements were taken in the first ten patients, affected by primary gonarthrosis and implanted with a resurfacing posterior-stabilised prosthesis in the period July 2010 – May 2011. A standard knee navigation system was enhanced by a specially-designed patellar tracker, mounted with a cluster of three light emitting diodes. Standard procedures for femoral and tibial bone preparation were performed according to the navigation system, and the patellar was resurfaced. Relevant resection planes were taken by an instrumented verification probe. Final position of the three components and lower limb alignment were also acquired. Joint kinematics was deduced from the anatomical survey, which included anatomical landmarks on the patellar posterior aspect, and according to established recommendations and original proposals.INTRODUCTION
METHODS
Restoration of natural range and pattern of motion is the primary goal of joint replacement. In total ankle replacement, proper implant positioning is a major requirement to achieve good clinical results and to prevent instability, aseptic loosening, meniscal bearing premature wear and dislocation at the replaced ankle. The current operative techniques support limitedly the surgeon in achieving a best possible prosthetic component alignment and in assessing proper restoration of ligament natural tensioning, which could be well aided by computer-assisted surgical systems. Therefore the outcome of this replacement is, at present, mainly associated to surgeon's experience and visual inspection. In some of the current ankle prosthetic designs, tibial component positioning along the anterior/posterior (A/P) and medio/lateral axes is critical, particularly in those designs not with a flat articulation between the tibial and the meniscal or talar components. The general aim of this study was assessing in-vitro the effects of the A/P malpositioning of the tibial component on three-dimensional kinematics of the replaced joint and on tensioning of the calcaneofibular (CaFiL) and tibiocalcaneal (TiCaL) ligaments, during passive flexion. Particularly, the specific objective is to compare the intact ankle kinematics with that measured after prosthesis component implantation over a series of different positions of the tibial component. Four fresh-frozen specimens from amputation were analysed before and after implantation of an original convex-tibia fully-congruent three-component design of ankle replacement (Box Ankle, Finsbury Orthopaedics, UK). Each specimen included the intact tibia, fibula and ankle joint complex, completed with entire joint capsule, ligaments, muscular structures and skin. The subtalar joint was fixed with a pin protruding from the calcaneus for isolating tibiotalar joint motion. A rig was used to move the ankle joint complex along its full range of flexion while applying minimum load, i.e. passive motion. In these conditions, motion at the ankle was constrained only by the articular surfaces and the ligaments. A stereofotogrammetric system for surgical navigation (Stryker-Leibinger, Freiburg, Germany) was used to track the movement of the talus/calcaneus and tibial segments, by using trackers instrumented with five active markers. Anatomical based kinematics was obtained after digitization by an instrumented pointer of a number of anatomical landmarks and by a standard joint convention. The central point of the attachment areas of CaFiL e TiCaL was also digitised. Passive motion and ankle joint neutral position were acquired, and the standard operative technique was performed to prepare the bones for prosthesis component implantation. The final component for the talus was implanted, the tibial component was initially positioned well in front of the nominal right (NR) position, the meniscal bearing was instrumented with an additional special tracker, and passive motion was collected again in passive flexion. Data collection was repeated for progressively more posterior locations for the tibial component, for a total of six different locations along the tibial A/P axis: three anterior (PA), the NR, and two more posterior (PP), approximately 3 to 5 mm far apart each. The following three-dimensional kinematics variables were analyzed: the three anatomical components of the ankle joint (talus-to-tibial) rotation (dorsi/plantar flexion, prono/supination and internal/external rotation respectively in the sagittal, frontal and transverse planes), the meniscal bearing pose with respect to the talar and tibial components, the ‘ligament effective length fraction’ as the ratio between the instantaneous distance between the ligament attachment points and the corresponding maximum distance, and the instantaneous and mean helical axes in the tibial anatomical reference frame. In all specimens and in all conditions, physiological ranges of flexion, prono/supination and internal/external rotation were observed at the ankle joint. A good restoration of motion was observed at the replaced joint, demonstrated also by the coupling between axial rotation and flexion and the physiological location of the mean helical axis, in all specimens and in most of the component positions. Larger plantar- and smaller dorsi-flexion were observed when the tibial component was positioned more anteriorly than NR, and the opposite occurred for more posterior positions. In regards to the meniscal bearing, rotations were small and followed approximately the same patterns of the ankle rotations, accounted for the full conformity of the articulating surfaces. Translations in A/P were larger than in other directions, the bearing moving backward in plantarflexion and forward in dorsiflexion with respect to both components. It was observed that the closer to NR the position of the tibial component is, the larger this A/P motion is, accounted mainly to the associated larger range of flexion. The change of CaFiL and TiCaL effective length fraction over the flexion arc was found smaller than 0.1 in three specimens, smaller than 0.2 in the fourth, larger both in more anterior and more posterior locations of the tibial component. The simulated malpositioning did not affect much position and orientation of the mean helical axis in both the transversal and frontal planes. The experimental protocol and measurements were appropriate to achieve the proposed goals. All kinematics variables support the conclusion that the ankle replaced with this original prosthesis behaves as predicted by the relevant computer models, i.e. physiological joint motion and ligament tension is experienced resulting in a considerable A/P motion of the meniscal bearing. These observations are particularly true in the NR postion for the prosthesis, but are somehow correct also in most of the tibial malpositions analysed, in particular those on the back.
Multiple ACL revisions represent an extremely demanding surgery, due to the presence of enlarged or malpositioned tunnels, hardware, injuries to the secondary stabilizers and difficulties in retrieving autologous tendons. An anatomical ACL reconstruction is not always possible. We analyzed the results in a series of patients operated with over the top reconstruction (OTTR) and lateral extra-articular plasty to the Gerdy's tubercle (LP) using Achilles (AT) or tibialis posterior tendon (TPT) allografts. From 2002 to 2008, twenty-four male athletes with a mean age of 30.8 years were operated. 20 of the patients had two, while four patients had three previous reconstructions. IKDC score and KT evaluation were used at a mean 3.3 years follow-up (2–7 years).Introduction
Methods
Osteocondritis dissecans (OCD) is a relatively common cause of knee pain. Ideal treatment is still controversial. Aim of this exhibit is to describe the outcomes of 5 different surgical techniques in a series of 63 patients. 63patients (age 22.5±7.4 years) affected by OCD of the femoral condyle (45 medial and 17 lateral) were treated by either osteochondral autologous transplantation, autologous chondrocyte implantation with bone graft, biomimetic nanostructured osteochondral scaffold (Maioregen) implantation, bone-cartilage paste graft or bone marrow derived cells transplantation “one-step” technique. Patient evaluation included IKDC score, eq-vas score, X-Rays and MRI preoperatively and at follow-up. Global mean IKDC improved from pre-operative 40.1±14.6 to 77.2±21.3 (p<0.0005) at mean 5.3±4.7 years follow-up, while eq-vas improved from 51.7±17.0 to 83.5±18.3(p<0.0005). No influence of age, size of the lesion, length of follow-up and associated surgeries on the result was found. No differences were found between the results obtained with different surgeries except a slight tendency of better improvement in the result following autologous chondrocyte implantation (p<0.01). Control MRI evidenced a satisfactory repair of cartilaginous layer and subchondral bone. The techniques described were effective in providing good clinical and radiographic results in the treatment of OCD and confirmed the validity of autologous chondrocyte implantation over time. Newer techniques such as Maioregen implantation and “one-step” base on different rationales, the first relying on the characteristics of the scaffold and the second on the regenerative potential of mesenchymal cells. Both of them have the advantages to be minimally invasive surgeries and to require a single operation.
High grade hallux rigidus is a forefoot deformity characterized by a limitation of dorsiflexion of the first toe associated with pain, and severe damage of the first metatarsophalangeal joint. Most authors recommended resection arthroplasty or arthrodesis of the first metatarsophalangeal joint. The aim of this study was to present the results of our series of 42 consecutive cases of severe hallux rigidus treated by resection of the first metatarsal head and implant of a poly D-L lactic (PDLLA) bioreabsorbable spacer to promote the interposition of fibrous tissue to preserve the range of motion of the joint. Forty-two feet in 27 patients affected by high grade hallux rigidus were included in the study. Surgical treatment consisted of resection of the first metatarsal head and positioning of a poly D-L lactic acid (PDLLA) bioreabsorbable implant. Post-operative care consisted in gauze bandage of the forefoot, and immediate weight-bearing with talus shoes for 3 weeks. All patients were clinically and radiographically evaluated preoperatively and checked at a mean 6 (5–7) year follow-up.Objective
Material and methods
Metal-on-metal hip resurfacing (MOMHR) is a good surgical indication for young active patients. However, it cannot be used in patients with an excessively short femoral head/neck. To address these cases, a new surgical technique has been developed comprising femoral head augmentation using impacted morcellized bone grafts. 32 osteoarthritis patients who had severe congenital insufficiency of the femoral head/neck were treated with MOMHR combined with femoral head augmentation. Mean patient age was 49 ± 9 years (18–66). The required amount of augmentation was calculated on preoperative X-rays and confirmed during surgery. Using specially designed instrumentation, bone chips produced while reaming the socket and trimming the head were impacted onto the head to achieve the desired reconstruction and lengthening. Finally, the femoral component was cemented.Introduction
Methods
Combined metatarso-phalangeal and inter-phalangeal deformity represents about 1% of hallux valgus deformity, and its treatment remains a debated topic, because a single osteotomy does not entirely correct the deformity and double osteotomies are needed. The aim of this study is to review the results of 50 consecutive combined metatarso-phalangeal and inter-phalangeal hallux valgus treated by Akin proximal phalangeal osteotomy and SERI minimally invasive distal metatarsal osteotomy. Fifty feet in 27 patients, aged between 18 and 75 years (mean 42 years) affected by symptomatic hallux valgus without arthritis were included. Two 1-cm medial incisions were performed at the metatarsal neck and at proximal phalanx. Then SERI osteotomy was performed to correct metatarso-phalangeal deformity and Akin osteotomy was performed to correct interphalangeal deformity. Both osteotomies were fixed with a single K-wire. A gauze bandage of the forefoot was applied and immediate weight-bearing on hindfoot was allowed. K-wire was removed after 4 weeks. All patients were checked at a mean 4 year follow-up.Objective
Material and Methods
Computer-assisted techniques in total knee replacement (TKR) have been introduced to improve bone cuts execution and relevant prosthesis components positioning. Although these have resulted in good surgical outcomes when compared to the conventional TKR technique, the surgical time increase and the use of additional invasive devices remain still critical. In order to cope with these issues, a new technology in TKR has been introduced also for positioning prosthetic components according to the natural lower-limb alignment. This technique is based on custom-fit cutting block derived from patient-specific lower-limb scan acquisition. The purpose of this study is to assess the accuracy of the custom-fit technology by means of a knee surgical navigation system, here used only as measurement system, and post-operative radiographic evaluations. Particularly, the performances of two different custom-fit cutting blocks realized from as many scan acquisitions have been here reported. Thirty patients affected by primary knee osteoarthritis were enrolled in this study. Fifteen patients were implanted with GMK® (Medacta-International, Castel San Pietro, CH) and as many patients with Journey® (Smith&Nephew, London, UK). Both TKR designs were implanted by using custom-fit blocks for bone cut executions provided by the same TKR manufacturers according to a pre-operative web planning approved by the surgeon. Particularly, the cutting block for the former design was built from CT scan acquisition of the hip, knee and ankle, whereas that for the latter design from MRI scans acquisition of the knee and X-ray lower-limb overview. A knee surgical navigation system (Stryker®-Leibinger, Freiburg, Germany) was used for recording intra-operative alignment of bone cuts as performed by means of the custom-fit cutting blocks and relevant component positioning. Prosthetic components alignments were also assessed post-operatively on X-ray images according to a shape-matching technique. The accuracy of the custom-fit blocks was evaluated through the comparison between pre-operative planning, and intra/post-operative data. Discrepancies above 3° and millimeters were considered as outliers. Within the patient cohort, nine cases were fully analyzed at the moment and here reported. Over them and except for one case, the discrepancy between pre-operative planned femoral/tibial resection level on the frontal plane and the corresponding measured intra-operatively was within 3 mm, being 5 mm in the worse case. Two outliers were observed for the corresponding femoral/tibial cut rotational alignment. Particularly, in one patient, the discrepancy in femoral cut alignment was of 8° in flexion and 6° in external rotation; in another patient this was of 4° in extension and 4° in external rotation in the femoral and tibial cut alignment, respectively. Post-operative radiographs evaluations for the final prosthetic components revealed that femoral/tibial alignment were within 3° in all cases, except for those patients that were already outliers. These preliminary results reveal the efficacy of the custom-fit cutting block for TKR. These were generally fitted properly and final prosthetic components were accurately placed, although some discrepancies were observed. This new technology seems to be a valid alternative to conventional and computer-assisted techniques. More consistent conclusions can be deduced after final evaluation of all patients.
ACL (anterior cruciate ligament) partial tears include various types of lesions, and an high rate of these lesions evolve into complete tears. Most of the techniques described in literature for the surgical treatment of chronic partial ACL tears, don't spare the intact portion of the ligament. Aim of this study was to perform a prospective analysis of the results obtained by augmentation surgery using gracilis and semitendinosus tendons to treat partial sub-acute lesions of the ACL. This technique requires an “over the top” femoral passage, which enables salvage and strengthening of the intact bundle of ACL. The study included 97 patients treated consecutively at our Institute from 1993 to 2004 with a mean injury-surgery interval of 23 weeks (12–39). Patients were followed up by clinical and instrumental assessment criteria at 3 months, 1 year and 5 years after surgery. Clinical assessment was performed with the IKDC form. Subjective and functional parameters were assessed by the Tegner activity scale. Instrumental evaluation was done using the KT-2000 instrument: the 30 pound passive test and the manual maximum displacement test were performed. We obtained good to excellent results in 95.9% of cases. We didn't observed recurrences in ligamentous laxity. We believe that the described technique has the advantage of being little invasive, compatible with the ACL anatomy, and enables very rapid functional recovery and return to sport.
Fresh bipolar shell osteochondral allograft (FBOA) is a controversial treatment option for post-traumatic ankle arthritis. Immunological response to transplanted cartilage may play a role in failure. Aim of the study is to compare two groups of patients who received FBOA in association or not to immunosuppressive therapy. 2 groups, of 20 patients each, underwent FBOA. Only one group (group-B) received immunosuppressive therapy. Pre-operative and follow-up evaluation were clinical (AOFAS) and radiographical (X-Rays, CT- scan, MRI). Bioptic samples harvested during II look were examined by histochemical, immunohistochemical (ICRS II score) and by genetic typing analyses.INTRODUCTION
METHODS
Although the number of displaced femoral neck fractures treated with hip arthroplasty is steadily growing, the outcomes are not as good as for other surgical indications. As a result, there is no consensus on the ideal type of arthroplasty for these patients. Unipolar and bipolar arthroplasty have a low dislocation rate but implant longevity and functional results are suboptimal. Total hip arthroplasty (THA) provides better functional outcomes and implant longevity but it is associated with a high incidence of postoperative dislocation. This constitutes a significant limiting factor for a more widespread use of this procedure. The TriboFit® Buffer (Active Implants Corporation, Memphis, Tennessee, USA) is a 2.7 mm-thick cup made of polycarbonate-urethane which mimics the mechanical characteristics of human cartilage. It is a pliable, hydrophilic, biocompatible, endotoxin-resistant material and acts as a stress-absorber, transmitting loads to the subchondral bone in a physiological manner. The TriboFit® Buffer shows excellent tribology, including ideal fluid film lubrication, low friction, high load carrying capabilities and long endurance. The TriboFit® Buffer is fixed using flexible mechanical fixation. With a special instrument, a circumferential groove is cut into the patients’ socket. The TriboFit® Buffer is seated by applying gentle pressure, with its ledge snapping tightly into the groove. The surgical technique is bone sparing as no acetabular bone reaming is required whatsoever. The TriboFit® Buffer can be coupled with large diameter cobalt-chromium femoral prosthetic heads of the same dimensions as the patients’ femoral head. By restoring the correct hip anatomy and preserving the original size of the femoral head, hip range of motion (ROM) and stability are optimised. Within a multi-centre study, 224 patients (63 male and 161 female) with femoral neck fractures were treated with the TriboFit® Buffer, a large diameter head and either cemented (192) or uncemented femoral stems (32). The mean patient age was 83 years (range 65 to 96). All surgeries were performed using a standard antero-lateral approach. Rehabilitation was fast and weight-bearing was as tolerated by the patients. There were no major complications, and in particular, no postoperative dislocations were reported. At a mean follow-up of one year, X-rays showed good implant stability. The mean Harris hip score (HHS) after one month was 58 points and increased to 80 points at one year (p = <
0.05). The ROM was the same as in the intact hip. Only one patient was revised because of nonimplant-related pain. This patient complained of pain in the surgically treated limb which was in actual fact related to spinal stenosis. Analysis of the retrieved implant revealed a loss of thickness in the superior area as well as minimal weight (approximately 2.4%). The backside revealed evidence of macroscopic wear in the area of directional loading from the femoral head to the acetabulum. The bearing surface showed minimal wear (less than 15 mm3), indicating that the primary wear location was on the backside. Retrieved synovial fluid and tissue analysis confirmed that there was no reactivity and no sign of synovitis. With femoral neck fracture patients, TriboFit® Buffer arthroplasty is theoretically superior to both hemiarthroplasty and THA as it should involve the same low risk of dislocation and acetabular bone preservation associated with hemiarthroplasty, together with the same good functional results and consistent implant longevity of THA. Other advantages of this technique include reduced bleeding and short surgical times. The results of this study show that the new TriboFit® Buffer arthroplasty technology has the potential to revolutionize the surgical treatment of displaced femoral neck fracture.
Although metal-on-metal hip resurfacing (MOMHR) is becoming a well accepted indication for young active patients with hip deformities, it does not come without its disadvantages. Longterm bone atrophy, serum metal ion elevation, metal ion hypersensitivity and the formation of pseudotumours have all been reported in the literature. It is thus clear that there is a need for novel bearing technology. A potentially revolutionary hip resurfacing system comes in the form of the TriboFit® Hip System, which comprises a 2.7 mm-thick acetabular buffer made of polycarbonate-urethane, a hydrophilic, biocompatible, endotoxin-resistant material which mimics the fluid film layer naturally present in hip joints. This is a pliable implant whose modulus of elasticity is the same as that of normal human cartilage, thus providing optimum shock absorption. In addition, it induces lubrication, which is of the utmost importance as friction is almost eliminated, resulting in a subsequent decrease in the production of wear particles. Indeed, in vitro studies have shown that metal wear is 7-fold less than with a comparable metal-on-metal implant. The TriboFit® Buffer is implanted using flexible mechanical fixation. With a special instrument, a circumferential groove is cut into the patients’ socket. The TriboFit® Buffer is seated by applying gentle pressure, with its ledge snapping tightly into the groove. The surgical technique is bone sparing as no acetabular bone reaming is required whatsoever. The TriboFit® Buffer can be coupled with a select number of metal hip resurfacing femoral components. In our centre, we have used this novel bearing technology to treat patients with both osteoarthritis (two patients) and avascular necrosis (four patients). The mean patient age was 50 years (range 30 to 63). In five patients who had a well preserved socket anatomy, the TriboFit® Buffer was implanted without reaming the acetabular bone. In one patient with significant osteoarthritic changes of the socket, the TriboFit® Buffer was inserted into a specially manufactured uncemented metal shell, using the TriboFit® Buffer as a liner. The socket was reamed according to the standard reaming technique. In two patients a Birmingham hip resurfacing (BHR) femoral component was used and in the other four an ADEPT component was used. Rehabilitation was fast and uncomplicated. The mean follow-up of these patients was one year. The mean preoperative Harris hip score (HHS) was 62. The mean HHS at one year was 99 (p = <
0.05). X-rays showed good quality bone at the bone-implant interface. No osteolysis, loosening, or bone rarefaction was observed. At follow-up, two patients resumed sporting activities. One patient resumed skiing while the other resumed biking. Our pilot study shows that TriboFit® Buffer hip resurfacing arthroplasty is a valid alternative to MOMHR. Compared to the latter, the major advantage includes significantly lower metal wear generation, without any differences in the functional results. This new technology has the potential to expand the use of hip resurfacing to patients with renal malfunction, metal ion allergy/hypersensitivity and to fertile females.
